EXHIBIT 10.18


October 29, 1998


Mr. Steven M. Samowich
5 Brimstone Lane
Acton, MA  01720

Dear Steve:

We are pleased to that you will be joining  Infodata Systems Inc. as President
and Chief Executive Officer effective November 3, 1998. In this position,  you
will report to the Board of Directors and its Chairman,  Richard T.  Bueschel.
You will  perform such duties as are  consistent  with these  titles,  and any
other duties  reasonably  assigned by the board. You will also be appointed to
serve on the Board of Directors.

As the  Company's  Chief  Executive  Officer,  your annual base salary will be
$251,400  per  year,  payable  biweekly.  You will  participate  in an  annual
incentive bonus plan of forty percent (40%) of base salary with no cap (with a
guaranteed  minimum  of  $45,000  for  1999).  This  bonus  will be based upon
mutually  agreed  performance  achievements  against both personal  management
objectives  (20%)  for the year and  selected  company  financial  performance
measures  (80%).  If you  exceed  the  financial  measures  your bonus will be
increased more than  proportionally.  We will agree on these  measures  during
your first sixty days of  employment.  In  recognition  of your  leadership at
Infodata,  you will be awarded  options to acquire  220,000 shares of Infodata
stock at a price of $3.00 per share, which will vest to you as follows:
      12.5% six  months  from the start of your  employment,  and 6.25%  every
      three months thereafter.
This vesting is contingent on your  continued  employment on those  respective
dates.

The level of your salary will be reviewed  annually by the Board. You will, of
course, be eligible to participate in the Company's Stock Option grant program
going  forward.  The  amounts of any such  future  grants  are  subject to the
approval of the Board of  Directors.  In addition,  you will receive a $31,923
hiring bonus.  We will also pay $25,000 toward the expenses  incidental to the
sale of your house and $5,000 of your moving expenses.

You will be entitled to three weeks of vacation  annually and will participate
in the  Company's  benefit  plans  available to our other  senior  executives,
including  health  insurance,  401(k) plan, and other programs.  Infodata will
provide you with a life  insurance  policy with a death benefit of $1,000,000,
long-term  disability  insurance  that pays a  benefit  of  $10,000  per month
tax-free and will pay for an annual medical examination.


<PAGE>

It is understood that your employment at Infodata is terminable-at-will and is
not for any definite  term.  However,  Infodata  agrees that in the event that
your employment is terminated by the Company,  other than for cause,  you will
continue  to be paid  your  base  salary  for a period  of  twelve  months.  A
termination  for cause will be defined as a termination by the Company of your
employment  due to (a) the  failure or refusal of the  Employee  to follow the
lawful directives of the Board or designee (except due to sickness, injury, or
disabilities),  which directives are substantially  consistent with Employee's
employment  responsibilities  hereunder,  (b) gross  inattention  to duty, (c)
willful,  reckless, or grossly negligent act (or omission to act) by Employee,
in connection with the performance of his duties,  including failure to follow
the policies and  procedures  of the  Company,  (d) a material  breach of this
Agreement by Employee,  or (e) the commission by Employee of a felony or other
crime  involving  moral  turpitude or the  commission by Employee of an act of
financial dishonesty against the Company.

Please  confirm your  acceptance  of this offer and its terms by signing below
and returning a signed copy of this agreement to me.

As I am sure you  already  know  from the time we have been  together,  we are
excited about your coming to Infodata and leading the next steps in our growth
and business  performance.  On behalf of our entire board,  we look forward to
working  together in the years ahead.  I will plan on seeing you on Wednesday,
November 4, 1998.  I have  changed  the  all-hands  meeting to a reception  at
4:00pm for you to meet the employees in an informal setting.

 Sincerely


 /s/RICHARD T. BUESCHE
 ----------------------
 Richard T. Bueschel
 Chairman of the Board,
 Infodata Systems Inc.


                                                         Accepted:

                                                         /s/STEVEN M. SAMOWICH
                                                         ---------------------
                                                         Steven M. Samowich